Right-click the cell that contains the field [Qty] , and click Add Total. This adds a sum of the quantity for each order to the totals row. In the empty cell to the left of Sum[Qty] , type the label  Order Total . You can add a background color to the totals row. Select the two sum cells and the label cell.
Ladder logic is the first in a series exploring different software programming methods how to choose the most appropriate model of computation based on system requirements and architecture. Future articles will cover textual, function block/data flow, state chart, and simulation and modeling methods.
MOV (Move) Ladder Logic Instruction. The Move instruction is a ladder logic rung output instruction that copies the Source value and places a copy in the Destination tag. The Source remains unchanged. The instruction is enabled when the preceding logic is true and disabled otherwise. The values can be constants, tags or any combination.